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A170826
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a(n) = GCD(n^2, n!).
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4
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1, 2, 3, 8, 5, 36, 7, 64, 81, 100, 11, 144, 13, 196, 225, 256, 17, 324, 19, 400, 441, 484, 23, 576, 625, 676, 729, 784, 29, 900, 31, 1024, 1089, 1156, 1225, 1296, 37, 1444, 1521, 1600, 41, 1764, 43, 1936, 2025, 2116, 47, 2304, 2401, 2500, 2601, 2704, 53, 2916
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OFFSET
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1,2
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LINKS
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Table of n, a(n) for n=1..54.
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FORMULA
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If n is prime then a(n)=n else if n<>4 then a(n)=n^2. - Zak Seidov, Dec 28 2009
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MAPLE
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GCDWITHFACTORIAL:=proc(a) local b, i, k:
if whattype(a) <> list then RETURN([]); fi:
b:=[]:
for i to nops(a) do b:=[op(b), gcd(a[i], i!)]: od;
RETURN(b);
end:
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PROG
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(PARI) a(n)=if(isprime(n), n, if(n==4, 8, n^2)) \\ Charles R Greathouse IV, Feb 01 2013
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CROSSREFS
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Sequence in context: A190997 A184392 A007955 * A162537 A109844 A128779
Adjacent sequences: A170823 A170824 A170825 * A170827 A170828 A170829
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KEYWORD
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nonn,easy
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AUTHOR
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N. J. A. Sloane, Dec 27 2009
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STATUS
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approved
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